Werecats are sentient creatures with shapeshifting abilities, being able to take on the appearance of either a human or a large, shaggy cat. Whether they migrated to Alagaësia or were native to the land was unknown. They were quite rare; the few who were alive during Eragon's time did not often reveal themselves.
Werecats were said to be very smart and dangerous at times.
It is unknown if werecats can use magic outside of their natural ability to change shape.
Werecats are also potentially the most deadly of all the races because so little is known about them and their knowledge is above all other races.
It is also noted that Eragon stated in Inheritance that he would rather fight a full grown Kull in opposition to fighting a single werecat due to their previously mentioned mystique and hidden power.
In Teirm, Eragon encountered a werecat named Solembum. Solembum was the companion of Angela the herbalist and showed affinity to Eragon; Angela told Eragon that it was unusual for Solembum to associate with any being other than herself, and that Eragon should feel honored. When Solembum shape-shifted, he appeared as a young boy with slanted eyes and a sprig of holly woven into his shaggy black hair.
Solembum aided and abetted Eragon's quest on more than one occasion. After Eragon's fortunetelling, he told Eragon a prophecy. ("When you are in need of a weapon, look under the roots of the Menoa Tree. When all seems lost and your power is insufficient, go to the Rock of Kuthian and speak your name to open the vault of souls.") Explanation: It spoke of a weapon under a tree that would someday be of use to him (which turned out to be brightsteel to forge his new sword, "Brisingr"). Solembum fought alongside the Varden in the Battle under Farthen Dûr and the Battle of The Burning Plains. He also inadvertantly aided Eragon in finding the reference to the Rock of Kuthian in Domia abr Wyrda through a spell placed on the werecats by the dragons.
In Ellesméra, Eragon met a female werecat by the name of Maud. She looked like an old woman with silver hair and pointed teeth. Her other names were Quickpaw, the Watcher, and Dream Dancer. She was the companion of Queen Islanzadí.
In Inheritance Grimrr Halfpaw, the king of the werecats, arrived at the Varden in his human form offering help. Grimrr was missing two fingers, had no clothes except a vest and loincloth, and looked young but worn. He carried a deep dislike of the herbalist Angela because of a trick she played on him. When she passed by and saw him torturing a bird instead of simply killing and eating it, she cast a spell on him that forced him to chirp like a bird whenever he tried to speak. This embarrassed him greatly among the werecats. Angela reminded him of it in the audience with Nasuada by simply saying "Cheep cheep".